Optical measuring instrument



Jan. 11, 1944. w, N, DE WALD l 2,339,004

OPTICAL MEASURING INSTRUMENT Filed Oct. 5, 1942 Patented Jan. 11, 1944UNITED STATES ATENT OFiJliIE.

OPTHCAL MEASURING INSTRUMENT Wiiliam N. De Wald, Miami, Fla.

Application October 5, 1942, Serial No. 460,912 (c1. esi- 2.4) I

3 Claims.

This invention relates to astronomical and other angle-measuringinstruments and more particularly to an cota-nt or a seXtant type ofdevice for use in marine and aerial navigation.

The prime object of the invention is to simplify the construction andarrangement of such instruments so as to not only minimize dii---culties in and cost of manufacture but toA also make for easymanipulation and elimination oi' confusion in use, without detractingfrom the requisite efficiency and accuracy in reckoning.

The particular advantages of the present invention will appear morefully and specifically in the following description of the illustrative,practical, construction and arrangement of an octant as shown in theaccompanying drawing, in which:

Fig. 1 is a side elevation;

Fig. 2 is a View, on an enlarged scale, partially foreshortened, and inpartial longitudinal section and side elevation, to sho-vv more clearlycertain interior details of construction;

Fig. 3 is a fragmentary view, in front elevation, to illustrate apractical indicator scale and correlated pointer;

Fig. 4 is a section on the line il-l ci Fig. 1;

Fig. 5 is a fragmentary sectional view taken on the line 5-5 of Fig. 4and on an enlarged scale; and,

Fig. 6 is a diagrammatic view illustrating the arrangement and ratio ofthe gear assembly shown in Figs. 4 and 5.

Referring now to the drawing in detail, the nu.- meral I0 designates,generally, the optical under or telescope portion of the instrument.This portion of the instrument, except for the parts ci the presentinvention that are incorporated to function therein and therewith, maybe of any conventional structure suitable for the purpose. As shown, theoptical finder lil includes the objective lens Il and the eyepiece l2provided with an outer lens I3 and an inner lens i4.

For the purposes of the present invention, the body tube of the opticalfinder l is cut away on its under and one side portion, for somedistance adjacent the eyepiece l2 as at i5 (see Figs. 2 and 4).Depending from the optical finder l), beneath this cutaway portion i5,is a sector-shaped housing i6 provided with a removable coverplate Il asone side wall thereof. As shown more clearly in Figs. 2 and 4, thehousing iS is provided vvith internal lugs Ii) to which the coverplatel1 is fastened by screws l.

Disposed transversely of the body tube of the optical finder l0 abovethe cutaway portion Iii thereof, is a transparent mirror 263. Thismirror as shown (see Figs. 4 and 5) is mounted within a frame 2| havinga trunnion 22 at one side and a somewhat longer trunnion 23 at itsopposite side (shown more clearly in Fig. 5).

The trunnion 22 is 'journalled in a bearing element 24 inserted (iixedlyin any approved manner) in an opening provided therefor in the wall ofthe body tube of the optical finder lil. The other trunnion 23 isextended through and has its intermediate portion journalled in asupporting bracket or gear-carrier-frame 25 that is attached to the topwall portion of the housing l (see Fig. 4). The outer end portion ofthis trunnion 23 is projected through an aperture 26 in the cover-plateil of the housing I6, and it is screw-threaded, as at 2l, for thereception of a nut 28 that covers the aperture 25 (see Fig. 5).

Mounted freely rotatable on the trunnions 22 and 23 are the opposedbifurcations or yoke eX- tensions 29 of a hollow, cylindrical,pendulumlike shell 30. This element 3@ has a transparent bubble-holder3i secured in its top portion. The holder 3| contains a characteristicliquid in which there is a conventional bubble that always finds aposition centrally of the holder Si and coincident with the longitudinalaxis of the pendulum shell 30 when the latter is hanging vertically fromthe trunnions 22 and 23 (see Fig. 2).

Just beneath the bubble-holder 3i is a translucent partition 33, whichmay be a disk of ground glass or any other suitable material. Under thiselement 33 is an electric light bulb SI1, the socket 35 for which isfitted centrally in a partition or other suitable transverse support 3&5provided for the purpose in the pendulum shell 3i). Below the light bulbsupport 36 is an electric dry battery 31'. The pole terminals of thebattery are held in electrical contact with the conventional terminalsof the light bulb socket 35 by a spring element 3B that is compressedagainst the lower end of the battery by a screwplug or other suitabletype of cap element 29 of the pendulum shell 3B (see Fig. 2).

The light from the bulb 34 in the arrangement of the several elementsthereaoove in the pendulum shell 30 illuminates the bubble 32 and pro--jects an image of the same onto the mirror 2li.

Any suitable switch (not shown) can be obviously provided and applied inany conventional manner for turning the light in the bulb 34 on and offat will. The same per se does not enter directly into the presentinvention. Hence, it is deemed unnecessary to illustrate it in detail inthe drawing.

When the optical nder l is horizontal and the pendulum shell 30vertically pendant, as shown in Fig. 2, the axial line of sight A of thefinder and the axial line of bubble image projection B from the pendulumshell are at right angles, i. e., ninety degrees (90) apart from eachother. Considering this the normal relative positions of the finder andpendulum shell, the transparent mirror 20 is set normally at an angle offorty-uve degrees (45) or, in other words, at one half (1/2) the anglebetween the finder line of sight A and line of bubble image projectionB, as shown in Fig. 2. So, too, the pivotal axis or the mirror 20 isdiametric of the finder tube and also coincident with the point ofintersection of the said lines of sight and bubble image projection Aand B, respectively.

The relative one-half angularity of the mirror with respect to theangularity of the intersecting lines or sight and bubble imageprojection. A and B is maintained by proportionate ratio adjustment ofthe mirror throughout the use oi' the instrument. That is to say, whenthe optical under it is trained on any particular object (in marine oraerial navigation, usually a star er other celestial body) it is moreoften tilted at an inclination from the horizontal and generally with.its forward end raised. Therefore, provtsion is made in accordance withthe present in rention for adjusting the pendulum shell 3E] to avertical position and at the same time proportionately adjusting themirror to the aforesaid one-hali angularity relative to the establishedangularity between the lines of sight and bubble image projection. Asimple yet practical and highly el'licient adaptation of the inventionfor this purpose will now be described.

As hereinbefore stated, the Lipper bifurcated portions or yokeextensions 29 of the pendulum shell 38 are hinged freely rotatable onthe trunnions 22 and 23 of the mirro-r frame El. New, to mechanicallyswing said pendulum shell on said trunnions and to hold it in itsadjusted position, at the same time in unison with an angularityindicator, an actuator and Controller shaft is located laterally fromthe mirror trunnion 2.? and provided with an external manipulating knobil by which it is conveniently rotated.

A pointer 42, provided with a hub portion at its upper end, is keyed orotherwise fastened on the shaft between the knob 4l and the cover-platell' of the housing i6 (see Figs. 4 and 5) rihe point-- er, in its normalposition shown in Fig. 1, extends vertically downward from the shaft413, with its pointed end portion 43 in register with the 90 mark on anarcuate scale 44 on the outerI face of the cover-plate I'l.

The scale 44 as shown in Fig. 3 is marked off in radial lines indicativeof degrees and numbered in multiples of ten, the 90 indication be*- ing,of course, directly vertical below the axis of the shaft 45. lThe othernumbers to the left of the 90 indication are decreasingly numbered downto the 30 indication. The 10 indication to the right of the 96indication may be marked 10 as shown, or, obviously, it may be marked100. iowever, the particular marking of the scale S may be varied, ifdesired.

The pointer 42 as thus mounted rotates with the shaft lli?. To move thepointer and the pendulum shell 3@ in unison and at the same angularity atoothed gear wheel 45 is keyed or otherwise fastened on the inner endportion of the shaft 40. This wheel 45 drives a toothed wheel 4S of thesame pitch diameter, iixed or formed integrally on the hub portion ofthe adjacent yoke extension 29 of the pendulum shell tu. This driving isthrough the intermediary of an interposed idler wheel 41, also of thesame pitch diameter and rotatable on a jackshaft 48, as shown moreclearly by the dotted-line circles in the diagram in Fig. 6. The ratioof this particular gear assembly is 1 to 1. Hence, the swinging movementof the pointer 42 and the pendulum shell 3S is equal.

To rock the mirror 29 through one-half the angle of swing of the pointer42 and the pendulum shell Si), a pinion 49 of smaller pitch diameterthan that of the respective wheels 45, d6 and 4l is keyed or otherwisefastened on the actuator and controller shaft il between the supportingbracket or gear-carrierwframe 25 and the cover-plate il (see Fig. 5).This pinion 49 is in mesh with an interposed idler pinion 5t, of thesaine pitch diameter, rotating on a jackshait 5l. The idler pinion 50 isin turn in mesh with a toothed gear wheel 52 of a pitch diameter doublethat of said pinion 5i?. The wheel 52 is keyed or otherwise fastened onthe trunnion 23 of the mirror frame 2l. The ratio of this gear assemblyof the two pinions 49 and 5i) of the same diH ameter and the wheel 52 ofdouble that diameter, as shown by dot-and-dash lines in Fig. 6, is 2 to1, i. e., each of the pinions is and 553 makes two revolutions to one ofthe wheel 52. Hence, the mirror Eil is rocked through an angle onlyonehalf that of the swing of the pointer d2 and the pendulum shell 3i?.

In accordance with the present invention, the gearing between theactuator and controller shaft lil and the mirror 2E! and the pendulumele* ment 3i) may be varied as to form and type for accomplishing theproportionate actuation and control of said parts.

In the use of the octant illustrated in the drawing and as hereindescribed, the observer trains the optical nnder or telescope |11!directly on the particular star or celestial body sought for areckoning. Upon accomplishing this he turns the knob 4l, which in turnactuates the respective chains of gears, until the pendulum-lil: element30 is vertically positioned so that the bubble 32 is coincident with thelongitudinal axis of the element 30. The bulb 34 having previously beenlighted the image of the bubble 32 is projected onto the axial portionof the mirror 2t where the axial line of sight A of the optical nder IDintersects the pivotal axis of the mirror and the line B of bubble imageprojection. At this time the pointer 42 is brought into registrationwith the mark on the arcuate scale 44 indicative of the angle ofinclination. of the optical finder IU relative to the verticallypositioned pendulum element 3Q.

At the same time the mirror 2G has been adjusted to an angle one-halfthat oi the angle between the axial line of sight A of the finder l?)and the line of bubble image projection B from the element Sil. Forexample, when the iinder l?? is horizontal as shown in Figs. l and 2,and the knob di has been manipulated to set the pendulum element 3@ invertical position and at right angles to the finder le, the mirror 2t!is brought to the 45 angle shown in Fig. 2, which is onehalf the anglebetween the intersecting longitudinal axes of the iinder and thependulum element.

By the same token, should the finder HJ be inclined, the pendulumelement 3i! is accordingly positioned vertically by manipulation of theknob lll as aforesaid. The pointer 42 is at the same time positioned toindicate the relative angularity of the instrument so as to attain thedesired reckoning with accuracy sufficient for navigation of marine andair craft.

By the use of an instrument constructed, arranged and manipulated inaccordance with the present invention, navigation reckonings are readilyand conveniently attained without confusion. This is principally becauseof the direct sighting of the object sought through the telescope oroptical finder l and the exceedingly simple yet highly eflicientprovision of the rockable transparent mirror 2i] with the actuating andcontrolling means which sets the mirror at the proportionate half anglewhen the adjustment of the bubble carrier pendulum 3i) is effected.

While the illustrative form and arrangement of instrument as shown andherein described embodies a practical and efficient adaptation of thepresent invention considerable alteration and modification thereof iscontemplated within the scope of the appended claims. The invention,therefore, is not limited to the specific details ci' construction andarrangement shown.

I claim:

i. An instrument of the character described, comprising a tubular,direct-observance, optical finder having a conventional eyepiece at oneend and an objective lens forward thereof, a transparent mirrorpivotally mounted within the finder tube and disposed transversely ofthe same between the eyepiece and the objective lens, the pivotal axisof the mirror being substantially medial thereof and coincident with thelongitudinal line of sight of the finder, the under and one lower sideportion of the finder tube being Cut away in the immediate region of thetransparent mirror and continuing between the mirror and the eyepiece, aclosed housing shell covering said cutaway portion but communicablytherethrough' and extending downwardly from the finder tube, a swingablependulum-like bubble-carrier-element depending into said closed housingshell from a support co-axially with the axis of the mirror, thelongitudinal axis of said bubble-carrier-element intersecting the lineof sight of the finder coincident with the axis of the mirror, a bubblelocated in a transparent holder within said carrier-element whereby thebubble is centered in the holder and coincident with the longitudinalaxis of the carrier-element when the latter is positioned vertically tointersect the finder line ci sight at various angular positions of thefinder, illuminable means below the bubble-holder in carrier-element forprojecting an image of the bubble upwardly along the longitudinal axisof said element and onto the mirror at the point of intersection, andcommonly manipulated means enclosed within said housing shell but havingan external manipulating element for positioning thebubble-carrier-element vertically, whatever may be the angular positionof the finder-tube, and for simultaneously tilting the mirror adjustablyin proportionately varied relation to the change in angularity betweenthe line of sight in the finder-tube and the intersecting longitudinalaxis of the bubble-carrier-element.

2. The structure as set forth in claim 1 and further describing, morespecifically, the actuating and controlling means for thebubble-carrierelement and the mirror as comprising a gear assemblyincluding an actuator and controller shaft having an externalmanipulating knob fastened thereon, a driving pinion fastened on saidshaft, a driven spur wheel, of twice the pitch-diameter of said pinion,secured co-axially to the mirror, an interposed idler pinion of the samepitch diameter as said rst mentioned pinion and internieshed therewithand with said spur wheel whereby each pinion makes two revolutions toone of the spur wheel and the mirror is rocked through an angle halfthat of knob rotation, an additional gear chain including a driving spurwheel fastened on said actuator and controller shaft, a driven spurwheel secured to the bubblecarrier-element coaxially with the pivotalaxis of support of said element, an idler spur wheel interrneshed withsaid driving and driven spur wheels, said three mentioned wheels beingof the same pitch-diameter whereby the bubble-carrier-element is made toswing through an angle equal to that of knob rotation, said gearing andparts mentioned in association with the wheels being located within theadjacent portion of the finder-tube and the housing shell attached toand depending from said tube in intercommuncation therewith, an arcuatescale on the outside of the housing shell, and a pointer fastened onsaid actuator shaft externally of the housing shell with its pointed endin cooperatively opposed relation to said arcuate scale, said pointermoving` in unison with and in parallel relation to thebubble-carrier-element to indicate on the scale the angular position ofsaid element relative to the finder-tube.

3. In an instrument of the character described, a tubular optical finderhaving an eyepiece and an objective lens forward thereof, a pivoted,transparent mirror having supporting trunnions at opposite sides, theaxis of the trunnions being diametric of the finder-tube andintermediate the eyepiece and objective lens and intersecting the lineof sight of the finder, the under and one lower side portion of thefinder-tube being cut away and a housing extension being provided on thetube to cover the cutaway portion, a pendulum-likebubble-carrier-element suspended freely rotatable on the mirrortrunnions with' its longitudinal axis intersecting the finder line ofsight coincident with the point of intersection of the trunnion axis, anactuator and controller shaft located laterally from the mirror, amanipulating knob on said shaft, a l to 1 ratio driving connectionbetween said actuator and controller shaft and saidbubble-carrier-element, a 2 to l driving connection between said shaftand said mirror, an arcuate scale on the outside of said housing, and apointer element on said actuator and controller shaft having its pointedend in cooperative indicating relation to said arcuate scale.

WILLIAM N. DE WALD.

